Steam Monster Game – Best Strategies to Win

1. Don't die. Expect to take about 300k damage on level 569. Energy Shields grant 100k health each, and are unlocked after 10 Light Armor and 10 Heavy Armor.
2. Keep your team alive. Use your Medics ability every 5 minutes if the middle health bars are up and there is no active healing. The leftmost health bar is shared with the number of dead players, who can be resurrected with the Resurrection item. Items are obtained via boss drops or bought at the start of the game using badge points (BP) from previous games (1 BP per 10 levels). These are normal monsters:
3. Click for gold to upgrade Shields and Farming Equipment (deals 1000 DPS even while Steam is closed). Between boss levels, use abilities to deal extra damage and take out the spawners first before they spawn more low-gold, time-wasting minions. Note that Tactical Nuke etc. target the last monster you've clicked.
4. Use the Raining Gold items on bosses. Not damage items. Raining Gold immediately copies 1% of the loot per click. As bosses have a lot of hitpoints, you can easily get all clickers multiple times the base loot, millions! To compare, level 549 Spawners give only 1730 gold per click. Bosses take up the entire screen and appear in a random lane on each level multiple of 10. This is a boss:
5. Multiply your damage via Elemental Damage and tier upgrades (a Railgun does 1000 damage per click). Mouseover the buttons to compare DPS increase and cost. As lane elements are random per level, and bonus increments are fixed, spread out your elemental levels.
6. Switch lanes. Help out other lanes and take advantage of their active abilities. The log shows events in all three lanes.
7. Check back to spend collected items and use your cooled-down abilities. Games reset every day at 16:00 UTC, so spend your items before that. Raining Gold works better at higher levels, so don't spend them all early or when a boss is about to die.
8. Buy smart. The defense, auto, and click upgrades currently have five tiers each. Each tier is ten times as good as the one before it and starts out cheap, so only buy an upgrade if it costs less than a tenth of what the next tier does. Remember that you'll probably be AFK most of the time, so defense and auto are best. Morale Boost unlocks at Auto-fire Cannon level 20.
9. Play again. Only buy Raining Gold (10 BP each) as that has the most lasting effect by allowing everyone to prepare for higher levels. Metal Detector is worthless as it needs to be active when a monster dies and earns less than Raining Gold. Remaining BP can be spent on early game items Treasure (2 BP) to help you upgrade and Pumped Up (1 BP) for a little health boost. Note: Like lunboks said, if you plan to stick around for a level multiple of 100, buy some Wormholes and use them there to skip the next 10 levels each and give every player 500k gold. With nukers and no cooldown boosts, you'll only be able to use a few wormholes, though:

Your Monster Summer Badge will track the level of the last boss you helped defeat. Cheating even gives you an easter egg at level 100,000,000.