Pick a campaign, kill infected for XP, and every level-up freezes the infected and offers three upgrade cards out of 18 - hold Shift and press A, W or D to take one - and the picks stack, Megabonk style.
What you get
All 13 official campaigns: press Play and a campaign picker opens on the first map (Dead Center, Dark Carnival, Swamp Fever, Hard Rain, The Parish, The Passing, The Sacrifice, No Mercy, Crash Course, Death Toll, Dead Air, Blood Harvest, Cold Stream). Shift + A/W/D chooses, Shift + S flips the page. Workshop campaigns work too.
A ramp that stretches over each campaign: the first map is the gentlest, every map after it hits harder, with bonus card picks when you arrive, and a boss Tank at the finale
XP and levels from every kill: common infected 1, specials 5, witch 25, the Tank 100
18 upgrade cards: damage, crit chance, attack speed (guns and melee), max HP, move speed, jump height, lifesteal, regen, armor, ammo refill, XP gain, special-infected damage, Bonk! (melee), Slippery (dodge), Killing Spree, Adrenaline Rush, Chain Blast (kills can explode nearby infected, with a fireball) and Nine Lives (get back up once when downed)
A live upgrade list on the left of the screen: every upgrade you own, its level and its total value
Your run carries from map to map
How it plays
Press Play: Melty starts Left 4 Dead 2 straight into the Left 4 Bonk mode with bot teammates. While a card screen is open the infected and your bots freeze, and you are rooted and cannot be hurt. A card is only taken while Shift is held, so running around never picks one by accident.
Good to know
Needs only Left 4 Dead 2. Megabonk is the inspiration; no Megabonk files are used.
The freeze needs cheats, so the game starts with sv_cheats on for your local game (achievements are disabled while it is on).
Single player with bots for now. Local play only - please do not use it on VAC-secured official servers.
Left 4 Dead 2 has no true pause, and its HUD text cannot be scaled, so the pick banner is as large as the game's HUD allows.
Built with Claude Code. Original scripts and text, MIT licensed; no game files included.
