What I'm currently working on:
Bugfixes. There is always bugs on the first release, especially in the multi-platform software, and detection of such bugs is what preview is for.
Different graphics cards do things slightly differently as well. Some graphics cards are very old and have drivers that crash if game as much as sneezes in wrong direction. Of course, that all needs to be fixed - if a card cannot run the game, the game must gracefully display a 'card is too old' message, but it is surprisingly difficult to get right - it is even worse to show this message on cards which can run it.
Gameplay. That's it, campaigns, missions, attack/defend, online leaderboard, multiplayer.
In response to the critique of gameplay: At the moment, it is more of a game engine demo, and gameplay is necessarily classic and minimalist - that's also why it is called a 'preview', with emphasis on pre and view.
A lot of people like minimalist gameplay, a lot of people dislike it, and of course, when the game is finished it will include fancy missions&campaigns as well as minimalist option. I, personally, prefer retro-minimalism in games - Tetris style (or even codename MAT style), but I understand that preferences vary a lot.
Ahh, and as for thepiratebay. You're welcome to put the 'free' demo version here, if you want to. If you're hardcode fan, you can mislabel it as full to make a decoy, I don't mind (in fact I'd rather prefer if it takes more time to find torrent. It has not been pirated yet though so don't bother searching). Just don't put full here, when I add multiplayer, someone else would be using your on-line play token (embedded in the game) instead of you.
Force polygons of equilibrium structures
2 years ago