Hacknet is a fun terminal hacking game. has a bit of a steep learning curve but there's enough guides online if you're having difficulty. Would 100% recommend if you're into computer networking or something along that line. I sure have learnt a few real life things in my (so far) 8 hours of playing. It's currently €3.39
TIS-100 is very similar in that it's a programming based puzzler. The game has you using a low-level language quite similar to assembly language. Pretty good if you like programming + this game helped with my computing A level a tiny bit :) It's currently €3.49