Paper.io 2

You control a coloured square that leaves a trail behind it. Loop the trail back to your own territory and everything inside becomes yours. Cross someone else's trail and they are out; let anyone cross yours and you are. It is an idea you understand in four seconds and it is genuinely tense for about a week.

How it plays

Rounds are short and played against a handful of opponents on a shared board. The whole strategic content is a risk calculation: staying inside your own territory is perfectly safe but claims nothing, and every square you gain requires being outside it with a trail exposed. Big greedy loops are where the points are and also where you die.

What's great

The core idea is excellent and needs no explanation whatsoever — hand the phone to anyone and they will be playing competently inside a minute. Rounds last a minute or two so it fits into any gap. Watching a huge, patiently-drawn territory get taken from you by one careless loop is a real feeling, and the game generates it reliably.

What holds it back

Depth runs out fast. Once you have worked out that small safe loops beat ambitious ones, there is not much left to learn, and the opponents are not interesting enough to change that. The free version is heavy with ads — an interstitial between rounds when rounds last ninety seconds is a poor ratio. The presentation is plain and the sense of progression is cosmetic only.