原文地址：

I added a new boss and now I have two of them. Here are the alien names so far: Worker, Eater, Hairy, Glider. Bosses are called Worker Boss (it looks like big Worker and spits small Workers) and Borg (it's cube-shaped and destructs into big cubes).

I also added the shield. I have drawn this nice shield icon before. I drew it using Inkscape and got inspiration from a some YT tutorial. I tried to follow the tutorial (it was for Adobe Illustrator, not Inkscape), but failed. So I started to observe some shields that I like and noted how it's just a bunch or curves and gradients. I slapped Hairy on it, it looks really nice. This might even become the application icon for Android.

Anyway, the shield can be invoked at any time. It lasts 20 seconds. There will be some powerups to upgrade the shield to last longer. If aliens hit the shield it loses energy much faster, so you should still try to shoot them down even if shields are up.

Shield graphics looks like force-field. It required some manual messing with Gimp to draw it nice as I wanted a nice circle-segment instead of straight line and casting a gradient shadow that way doesn't seem to be supported. Maybe there's some trick I don't know. So I combined multiple linear gradients at a different angle. It turned out really nice.

I tried adding some glow to the shield icon, but then it stands out too much. I'll leave the glowing for situation when powerup flies across the screen and you need to pick it up.

With these new graphics, it starting to look like a complete game. I'm still thinking where to place the score multiplier and whether the current wave should be shown.

I'm also thinking that player should be able to buy some powerups before playing, but this would require some coins or something like that, and with current, fast gameplay it simply would not fit. Maybe a some aliens could leave some crystals behind them or something like that or random powerups would show up. Or you would simply get as much coins as the number of waves you survived.