I have no aversion to spending money on mobile games, and some of my best experiences with iOS games have been paid for: Plants Vs Zombies, Hitman Go, Thomas Was Alone and Monument Valley to name but four. Still, the plethora of free-to-play games does allow me to try out new gameplay experiences more or less forever, as long as I’m willing to risk the intrusion of money-making schemes into your fun. Recently, I’ve been playing three F2P games that have taken very different approaches to monetising fun, with very different results.

Monetization-Lite: Capitals, NimbleBit

Capitals is a clever little app that combines a Scrabble-like word game with some simple head-to-head strategy. You and your opponent start with one space each (your “capital”) on a hexagonal board, and the aim is to grow your territory and ultimately conquer your opponent. You do this by claiming spaces: each space has a letter, and if you use the letter in a space connected to your territory, you expand into it. But if your opponent claims territory bordering yours, some of your territory will turn neutral again.

A huge amount of strategy emerges from this simple gameplay: Sometimes it’s better to avoid a big word in favour of shoring up your defences. Sometimes you see an opportunity to strike deep into your opponent’s territory. Sometimes you want to use up convenient letters so as to cramp your opponent’s options. In the games I’ve played, some have been brief and wild struggles, others chess-like confrontations of advance and retreat.

There’s not much to complain about on the gameplay front: a few games turned into slogs as I tried to grind my opponent down (or they tried to grind me down), but there’s plenty of fun to be had. All the same, you wonder whether NimbleBit thought out their F2P strategy very far. Right now you can pay for unlimited “lives,” which you can also claim by watching promotional videos (one view equals one life). It feels restrictive, and Nimblebit might have been better simply making this a cheap paid game instead. Still, they’ve been updating Capitals gradually since it came out, and they might yet get the balance right. In the interim, I’d recommend giving it a try.

Monetization-Heavy: Marvel Future Fight, Netmarble

I’m a comic book geek, and when it comes to superheroes, you can Make Mine Marvel. So a F2P fighting game starring a range of Marvel heroes, with good gameplay and high production values should be a winner, right? Future Fight certainly makes a good start, giving you three leading heroes (Iron Man, Captain America and Black Widow) to start with and plenty of free goodies just for logging in every day. But it then buries the whole experience under layers of complexity, social networking hooks and premium currencies.

The core gameplay is a lot of fun—the three hero types (brawler, speed and ranged), are each stronger or weaker against one of the other types. Missions last no more than two minutes, providing experience and equipment to improve your heroes, and there’s even a story illustrated with quick cut scenes before and after missions. So that’s fun. The problem is that managing everything else becomes a chore. There are multiple ways to improve your hero, multiple types of mission you can take on, and coins, gems and tokens galore to collect.

If you’ve got the patience to get to grips with all of this, there’s a rewarding game to be found under all of the cruft. However, I found myself reduced to logging in once a day to pick up my daily reward, telling myself that I’d try to get to grips with it later. I never did. It’s one of the problems of F2P—having paid nothing, I’m not invested, and the grind of gaining expertise and levelling up my characters has put me off. Which is a shame. This is a well-coded, slick and fun game that might have done better had it been paid-for with much less in the way of complications.

Just Right?: Fallout Shelter, Bethesda Game Studios

Fallout Shelter caused a lot of fuss when Bethesda announced it alongside Fallout 4 at E3 recently. As a promotional iOS app, trading on an established franchise name and using a F2P model, it could have been awful. It isn’t. In fact, it’s one of the friendliest F2P games out there, with an in-app purchase model that actually seems to work. (It’s currently at #18 in the top-grossing games in Ireland.) How did Bethesda manage this? By keeping things simple and sticking to the feel of the Fallout franchise.

Whimsical ‘50s nuclear paranoia might not seem like a good basis for a game, but it’s worked for Fallout for years. The main Fallout games have been roleplaying-focused, but this is a management game that charges you with creating a paradisiacal “Vault” in the midst of a post-apocalyptic wasteland. To do this, you’ll have to guide your vault dwellers to create food, water, energy and medical supplies, send them out to explore the wasteland, and encourage them to breed in order to swell your population. Do it right and everyone will be blissfully happy. Do it wrong and you’ll have miserable, radiation-raddled inhabitants who fall prey to radroaches, raiders and the occasional nuclear reactor fire.

The first ingredient that makes this game so appealing is the grace notes sprinkled across the game (equipment descriptions, wasteland explorers’ journals, and cheesy banter between dwellers—the writing is uniformly excellent). The second ingredient is an in-app purchase system that doesn’t intrude and even enhances the game. The standard currency is bottle-caps, with which you pay for new rooms (and occasionally resurrecting unlucky vault dwellers). The premium currency is lunchboxes, which serve as booster packs that contain equipment, caps or dwellers, some of them better than any you’re likely to find in game. You can earn these lunchboxes through the game, but the excitement of opening a new one is enough to encourage you to plonk down actual money for more.

It’s not a perfect game—the learning curve is a little steep if you don’t RTFM, and there’s a lack of depth in the challenges you’ll face as you build your Vault beyond 100 inhabitants. But even so, it manages the SimCity trick of making you feel proud of what you’ve created while allowing you to peek in on the lives of your dwellers and even get a little invested in their continued existence.