I played through the whole game twice now, and everything worked fine. Now, in my third game, I came across some strange bug:
I built an engine early in game, with linear story, mono sound, 2D graphics V2, savegame, gamepad and steering wheel. Then I started developing my next game using the engine (small, still in the garage office). When dev stage 1 shows up, I don’t have ANY dev options. I should have linear story, gamepad and savegame in dev stage 1, but there is NOTHING. The same goes for dev stages 2 and 3, NO options. I tried this several times with later engines, and later in game with medium games, it’s always the same: the dev options don’t show up, which means I had to create a PSOne game with basic sounds 
This didn’t happen in my first 2 playthroughs. Please fix this, it’s really annoying to have a great technology and being unable to use it because the game (GAME DEV TYCOON, not the games I create) won’t let me.
Done. If you need anything else, please tell me. Oh, and by the way: I really LOVE the game.
Oh, and a few more informations:
It’s the Windows 7 version of the game. I did my first 2 playthroughs where the error didn’t occur with version 1.3.2 of the game. I started some more games then, but ended up in bankruptcy, so the game where the problem occured is in fact not my 3rd, but the 10th or 12th I uninstalled the game, then checked for updates, found version 1.3.8. Installed that, but the problem is still there. It’s the saveslot with Heartcore Games.