M21 vs Biu Gun
Price, ratings, monetisation and update history for both apps, side by side — with what reviewers say about each.
M21
Read full descriptionHide full description
【M21-3X特工】是密室逃脱升级版，一款学霸专属的游戏！！让你的脑力与体力High起来！！ 也是一款城市实景探索解谜游戏，玩法新颖。玩家以特工身份通过APP接收任务 ，穿梭于商场或公园等搜寻通关线索，完成各种难度的特工解谜任务，在更广阔的空间感受烧脑体验！！ 我们不一样，不做传统、不玩机关、没有惊吓与夸张的装备，手机是你的通关工具，需要你在杂乱的环境中挑战你的观察力、逻辑力、协作力！！ 任务模式：单人任务、双人任务、内奸任务、团建任务等！ 游戏人数不限，可多人同时进行！
Biu Gun
Transform your devices into virtual firearms with realistic 3D models and immersive sound effects. Engage in thrilling shooting simulations using intuitive motion controls. Explore a vast arsenal of weapons for an authentic experience.
- Realistic 3D weapon models
- Extensive weapon collection
- Dynamic shooting experience
- Immersive sound effects
- Apple Watch control support
Read full descriptionHide full description
Turn your iPhone and Apple Watch into virtual guns! Experience realistic 3D weapon simulations, immersive sound effects, and thrilling shooting gameplay. Apple Watch control supported! Hyper-Realistic 3D Weapon Models: Every firearm is meticulously rendered based on real-world famous guns for an authentic experience. Extensive Weapon Collection: Assault rifles, flamethrowers, grenades, machine guns, pistols, shotguns, submachine guns, axes, swords, and more—there’s something for everyone! Dynamic Shooting Experience: Shake your Apple Watch or iPhone to fire, strike a pose, and let the bullets fly—rat-a-tat-tat! Immersive Sound Effects: Feel the power of every gun with high-quality audio, including the iconic "ping" of a Garand clip ejection. Download now and enjoy the most fun shooting experience!
Screenshots
Verdict
The clearest difference is price: M21 at Free against Biu Gun's $0.99. M21 also leads on iOS requirement (12.0 vs 15.6). Biu Gun's advantage is device support (4 vs 2). On update cadence, ads and in-app purchases there is nothing between them.
Scored on Price · Rating · Positive reviews · Number of ratings · Update frequency · Ads · In-app purchases · Monetization · Best chart rank · Devices · Requires iOS
M21 is free to download; Biu Gun costs $0.99 up front. Neither carries in-app purchases, so what you see is what you pay.
M21 ships an update every 5 weeks, Biu Gun every 3 weeks. The most recent releases landed on November 11, 2026 and November 12, 2026 respectively.
| Parameter | M21 | Biu Gun |
|---|---|---|
| Price | Free — better | $0.99 |
| Rating | — | 5.0 (2 ratings) — better |
| Positive reviews | — | 42.9% of reviews |
| Number of ratings | — | 2 — better |
| Update frequency | Every 5 weeks | Every 3 weeks — better |
| Ads | No | No |
| In-app purchases | No | No |
| Monetization | — | Paid |
| Devices | iPhone, iPod | iPhone, iPad, iPod, Apple Watch — better |
| Requires iOS | 12.0 — better | 15.6 |
| Further details — not scored | ||
| Size | 65 MB | 38 MB |
| Age rating | 9+ | 12+ |
| Developer | 广州惟为网络科技有限公司 | Haijian Yan |
In-app purchases
M21
No in-app purchases
Biu Gun
No in-app purchases
