Classic Doom 1 and 2. There’s gotta be over 100 levels if you count TNT and Plutonia, which I think were sold as Final Doom? Anyway, if you just get the base games for 1 and 2, there are thousands upon thousands of community made maps, including some total conversions, so you can play new Doom content until it physically pains you to continue.
Of course, I feel obligated to mention that even though it would be super easy to pirate the WAD files and play with a free modern source port like GZDoom, like absolutely trivial to find copies of DOOM.WAD and DOOM2.WAD floating around the net, probably showing up easily on Archive.org, but… Um… Where was I going with this? Oh, right, don’t pirate. Cheap on GOG last I knew.
That shit drives me nuts. Wanna be trusted with my life savings, but they can’t be bothered to implement modern security features until they’re already being phased out. I don’t know what will replace modern 2FA schemes, but I guarantee banks will adopt the current ones about three years after the replacements become standard.
Also, they’re charging you a poor tax for not having enough money, whether that’s a minimum balance or just accidentally spending a nickel more than you had on hand.