Games like Besiege

Scrap Mechanic is a multiplayer survival sandbox game that lets you build and create using powerful tools. Crash-landed on a strange planet, you must defend against hostile Farmbots and engineer your own adventures. Regular updates bring new content and optimizations to this imaginative, robot-filled world.

"Trailmakers is a physics-based vehicle construction sandbox game, where you can build and pilot cars, planes, and boats in a variety of environments. The game features a campaign mode, rally mode to learn building, and sandbox maps for creative building. Multiplayer mode supports up to eight players for cooperative or competitive gameplay. Use various weapons and blocks to build and customize your ultimate combat vehicle."

TerraTech is an open-world sandbox adventure where you design and build vehicles from various blocks to explore, scavenge, and battle across diverse environments. Featuring co-op and PvP multiplayer modes, stunning graphics, and a captivating soundtrack, it offers both creative freedom and intense combat challenges. Despite some bugs and grinding, its humor and replayability make for a fun, engaging experience.

"Instruments of Destruction" is a physics-based destruction game that lets players control a customizable destructive vehicle. Wreck, demolish, and annihilate various structures and environments with an arsenal of powerful weapons. With an emphasis on creative destruction and dynamic sandbox gameplay, each level presents new opportunities for chaos and mayhem.

Space Engineers is a sandbox game set in space, where players build, design, and maintain various types of space vessels and stations. It features both creative and survival modes, allowing players to either freely build and explore or survive in a hostile environment. The game also includes physics-based engineering and destruction, adding a layer of realism and challenge to space engineering.

"SimplePlanes" is a sandbox-style construction simulation game that allows players to build and fly their own aircraft. With realistic physics and an intuitive building system, players can design planes that range from simple gliders to complex military jets. The game also features a variety of challenges and missions to complete, as well as online sharing capabilities for custom-built planes.

"Brick Rigs" is a sandbox physics game where players can build and drive a variety of vehicles made from bricks, from cars and helicopters to fire trucks and tanks. The vehicles' physics are dynamic, allowing for realistic movement and destruction. The game features a multiplayer mode for racing, demolition derbies, and battles with friends, as well as a workshop for sharing and downloading user-created content.

"From The Depths" is a sandbox vehicle construction game where you can build and command battleships, planes, submarines, and more in intense battles. The game features a creative mode, a strategic campaign with eight factions, and a story mode. It also offers in-game planet, campaign, mission, and multiplayer map editors, as well as Steam workshop support for sharing your creations. Available on PC, Mac, and Linux.

Stormworks: Build and Rescue is a physics-based game that allows players to design, build, and pilot their own sea-rescue vehicles. Players must use their problem-solving skills to complete missions and rescue citizens in various challenging scenarios. The game also features a sandbox mode for open-ended creative play.

Poly Bridge is a physics-based puzzle game where you build bridges to carry vehicles to their destination. Use a variety of materials and budget carefully to create structures that are both functional and stylish. With sandbox and level progression modes, plus Steam Workshop integration, there's endless bridge-building fun to be had.