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[Arzgarb]

Hi all.

This month I had some free time in my hands, so I decided to make a small game. What resulted is "The Lair of the Giant Amoebas".

Spoiler: Screenshot (click to show/hide)

The game can be downloaded here, and you'll need Python and the pygame library to run it. It should be cross-platform (it works at least on Linux and Windows).

The goal of the game is to collect diamonds on each level, and not be eaten alive by the amoebas. They come in four colors: red ones attack you, green ones run away, yellow ones run away but attack if you come too close, and purple ones try to stay at a fixed distance (they all kill you if you run into them). The amoebas can also dissolve wooden walls for you. You move with the arrow keys, Esc quits the game, and if you feel like cheating, 'w' skips a level.

This is still a work in progress, so all comments are welcome.

EDIT: Newest version (0.1.1) available here. Use 'p' to pause the game.

[mendonca]

It's really hard! I haven't made it past level 2 yet ...

The amoeba behaviour is pretty cool, any chance of a brief explanation of how you achieve that effect?

In terms of gameplay, it works well in general, although I would say at this point it feels somewhat down to chance as to whether you can outpace an amoeba when trying to dodge them. If its possible to slow them down by a marginal amount say 10% or so, it might make it more fun to try and skirt round them.

Or perhaps just an option to quickly restart the level on death would be an alternative way to make it slightly less frustrating to play.

[Arzgarb]

Thanks for the feedback! I made it difficult on purpose, but I guess it quickly becomes frustrating to restart the game every time. I'll add a level restart option when I get to it I might also add a difficulty option that controls the speed of the amoebas.

The amoeba behaviour is pretty cool, any chance of a brief explanation of how you achieve that effect?

I'm glad you asked about the amoebas, because the game is largely an experiment with amoeba-like movement.

Spoiler: Technical explanation (click to show/hide)

I use a modified version of the cellular Potts model. Basically, in each 'tick' you cycle through the amoebas, and for each, randomly choose a cell (tile) near its border to be removed from its body or added to it. If doing so would cut the amoeba in two or otherwise break things, don't do anything, otherwise make the change with probability P. There are several 'ticks' between each update of the display.

Now, the probability P is calculated as follows. Each amoeba has a quantity called free energy, which it 'tries' to minimize. If the change would decrease the amoeba's energy, P is large, but if its energy would increase, P is small. In my case, the free energy is at its minimum if the amoeba has 16 cells in its body, has perimeter length 7, touches other amoebas as much as possible, and is at a certain distance from the player, depending on its color. There are many coefficients that I had to tweak by trial and error.

In short, you just randomly grow and shrink the amoebas, but choose the probabilities so that they (in the long run) preserve their size and correctly react to the player.

[mendonca]

Very interesting. Is the amoeba getting an end caught in the little two-tile sections a handy by-product of the behaviour - or a special case?

Or is that something that isn't supposed to happen?

[Arzgarb]

Very interesting. Is the amoeba getting an end caught in the little two-tile sections a handy by-product of the behaviour - or a special case?

Or is that something that isn't supposed to happen?

That was in fact an accidental by-product of how I choose whether a cell is eligible for being removed. I decided that it was good, and based levels 2 and 3 on it

[mendonca]

Aaah ... level 3.

I can't bring myself to skip level 2 yet. I'm sure I'll figure a way past that 2nd red amoeba ...

[miauw62]

Which version of Python do I need?

[Arzgarb]

Which version of Python do I need?

I have Python 2.7.3. It might work with other versions, but I'm not sure.

[Arzgarb]

Double posting for a new version (called 0.1.1), available here. It now has the option of restarting the current level upon death, four difficulty levels that control the attack speed of red and yellow amoebas, and a pause function (use the 'p' key). 'Hard' is identical to the original game. The difficulty levels have not been tested that much, and are subject to change based on your feedback.