I have a horrible time following this sorts of threads because I can never remember the link between names and effects. So I'm going to cheat and paste in the table.
| Efficient Missiles | Halves missile usage. Missiles have a smaller blast radius |
Doable in xml. Effect is okayish. Indigo attraction range unaffected by missile damage range. Lorentz Factor
When entering a room for the first time, for 10 seconds, the simulation runs slower, and you are smaller
My variant of this was that the player was immune to damage, but I think I like yours better.Go For Broke
If you finish a room with < 1/4 life and no shields, you gain double coins for that room. Variant: the less health you have, the more rewards you get.
No real way to do logic checks in the xml. Mechanics around the player taking damage are really awkward to work with, especially in the higher levels of difficulty where you can take 6 damage per shot. Scoundrel
Shops no longer sell items. Greatly increase drop rate.
The main drops are missiles and credits. The main shop function is to exchange shops for systems/weapons/modules. By removing the shops, you end up with a pile of cash and nothing to spend it on but levels. You also lose 25% of your module access. Adding double drops to bosses would potentially work, but in the end I don't think it adds anything but a bit of random variation.Demolitionist
All explosion sizes (negative ones included) are increased. (It's a net positive, like the extended-range missile lancher)
Not doable in xml. There are very, very few explosions actually. And it would muck up the Invader ;p. Long Haul
Small Max HP gain/level
Not doable in xml. Would open some options up for an expansion ideas. Having generic health upgrade as options being more frequent in the level up might work out. Hmm... Renewable Energy
Small Max Energy gain/Level
Same. Recycling
Killing an enemy has a chance of giving health, missiles, a key, or XP. (This is obviously similar to the green mech's ability. In the perks, it was only available to him when you level up.)
On my list already, but yeah its a good stable option. Fortunate
Each minor item has a chance to be one rank higher (single missiles give 2, doubles give 4, single coins go up to 3. I've modded mine to have rare 5-coins and 3 would go to 5. Too bad there's no "double health")
How did you go about doing that? Turret Master
Turret bullets hurt both players and enemies. Several variants on this: the bullets don't always damage enemies, or only some of the turrets are replaced
Turrets aren't frequent and useful enough for this to work out. Some turrets already do hurt enemies. Would also need some engine changes to work. Photoelectric
When you take damage, gain some energy
This goes in line with your previous damage to player based idea. The problem is the same. I've been trying to come up with interesting variants, but the raw damage in the late levels makes it awkward. Pizoelectric
When you take damage, emit a shock wave that briefly slows enemies
There are a series of similar items that are okay. However, when I play, I typically only take them only if there is nothing better. I don't want to get hit, and when I do, this typically isn't going to help. 
He Cheats
When you re-enter a shop, the items are rerolled. Preferably only once
Control over when/how the shop is rerolled is important. There is/should be a consumable that does this. Although I'm not sure if it is set to spawn. Improved Optics
As a gimmick it works, but if you go too big it causes massive pathfinding issues.
Lagrangian Optimization
Bots orbit at a larger radius. Attacking bots attack from a longer range
Would require source code changes and may be more trouble that its worth. We are trying to keep the players incentive to hide in a corner low. Giving extra range to things increases the viability of hiding strategies, so caution is suggested. Inertia
Greatly increased damage at short range, decreased damage at long range (or just shorten range)(Maybe just slow the bullets as they go?)
Tricky. The majority of weapon balance matters for bosses only (because the scrubs die to easily). Short-range encounters with bosses are deadly for the player. If you reduced the damage the player did at range, then this weapon would be a nightmare for boss fights. If you increased it at short-range, but kept it constant at long range it would probably work out better. In the end though, a pure DPS boost would be preferred because it is simpler. Shots can have a lifetime based on time or distance. If we slow shots, shots with time lifetimes would take a massive hit. The Railgun has this mechanic already built into it.Bouncy Balls - There is a modifier that you can add, reflect or ricochet I believe, its pretty straightforward.
