Need help with enemy spawn - Heaven's Fate v0.5

Guys I'm here to divulgate and ask help for you.

Now I'm developing a rework of my old project, Take to Heaven, focusing in mobile devices.

Here is the link: http://www.scirra.com/arcade/addicting-action-games/17303/heavens-fate-v05-take-to-heaven-rework

But the problem is, I need your help with the spawn method, as you can see in-game, it is a "bit" insane (that's why i disabled HP). I would like to know your suggestions about a better way to spawn the enemies, for example, if you have already played Colosseum Heroes at your Android Device, I would like a spawn method like this ok?

Hmm... why not make it that these zombies climb up the platform you have?

You can spawn the enemies at the lowest Z depth possible in the layer, play animation and move them up as the animation plays and when the animation ends, you bring them to the top of the Z player along with the player.

Another way is to spawn them at the end of the path (which I found out you can fall from). and have them walk towards the player. That way the player feels as if they are coming from the end of the path. Could place two gates/buildings at the paths ends for added realism.

Oh and S and D buttons don't do anything. Only the A button does damage the rest do nothing.

—, thanks for report this bug, but the problem is that I already knew about them

The first one was my mistake, since I forgot to put the portal (I will explain it below), this way the player will not get to this area and fall down.

The second one was "intentional", I disabled the other skills since it wasn't needed for the reason I published it, that is only get ideas and suggestions about the spawn method, like yours.

OK, let explain the portal thing: Have you ever played the game I mentioned before? If so, u'll know what i'm planning to do.. The thing is, in the end of the "level" there will be a locked portal, that will be only unlocked by killing the monsters till one of them "drop" the "item" needed to unlock it. I did it because my old version (link:http://www.newgrounds.com/portal/view/636410?id=636410) was so much "linear", the player couldn't walk freely in the scene, having to kill each monster after monster, making the game boring and tiring

Updated Topic: https://www.scirra.com/forum/viewtopic.php?f=180&t=112543